Probing propensity of grade 2205 duplex stainless steel towards atmospheric chloride-induced stress corrosion cracking

摘要

The propensity of grade 2205 duplex stainless steel towards atmospheric chloride-induced stress corrosion cracking at 50℃ has been investigated. Electron backscatter diffraction has been used to characterise as received and 750℃ heat-treated microstructures. Screening tests in chloride-containing aqueous environments were employed to investigate the corrosion behaviour of both microstructures. These tests indicated significantly increased corrosion rates when exposed to HCl or FeCl_3-containing environments. Stress corrosion cracking tests with atmospheric exposures for up to 12 months showed selective dissolution of the ferrite, accompanied by stress corrosion microcracks in the austenite. This work demonstrates that grade 2205 duplex stainless steel microstructure may be rendered susceptible to stress corrosion cracking under atmospheric exposure conditions at 50℃.